Alternating current punch



July 17, 1962 K. SCHRODER ETAL 3,044,337

ALTERNATING CURRENT PUNCH Filed June 11. 1959 fwvw A dfi ld ld Patented July 17,1962

3,044,337 ALTERNATWG CNI PUNCH Karl Schriider, 116 Hauptstrasse 13, Weinheim, Germany, and Leonhard Kochendiirter, Werderstrasse, Heidelberg, Germany Filed June 11, 1959, Ser. No. 819,525 1 (Jlaim. {CL 83-372) The invention relates to a punch operated by alternating current for punching holes in paper, cardboard, pasteboard and the like by means of conventional axially shiftable dies.

For perforating paper, cardboard, pasteboard and the like with the object of filing in wrappers, letter files and the like by means of two axially shiftable, spring loaded punching dies arranged in a housing at a distance apart, it is known to employ an electromagnet with a plunger armature constructed as a ram acting on the punching dies and to provide outside the housing a switching contact to be operated by hand or by foot. A direct current magnet fed through a rectifier is used as electromagnet. it has also been proposed to accommodate the rectifier and the switching contact in a common housing. The transmission of the movement of the ram of the electromagnet is effected by a two-armed lever. While such devices serve their intended purposes within certain inherent limitations, they have several disadvantages. To eliminate said disadvantages it is, therefore, the object or" the present invention to provide an alternating current punch in which the rectifier is omitted and which enables the apparatus to be connected up directly with the mains supply and thus produce a compact handy aggregate with small switching elements, so that finally all the component parts can be accommodated in a housing cover.

The subject matter of the invention is an alternating current punching apparatus for punching holes in paper, cardboard, pasteboard and the like material by means of conventional axially shiftable punching dies using an electromagnet as driving means for these punching dies with direct connection to the mains supply and a feeler lever for initiating the punching operation, and it consists substantially in that the current feed to the electromagnet is effected by the feeler lever through the intermediary of a microswitch and the armature of this electromagnet set in operation thereby actuates a retarding device through another microswitch interrupting the current feed for a predetermined time to allow the removal of the perforated material.

According to the invention the plunger armature in descending presses a piston efiectively cushioned in an air-filled cylinder downwardly through the intermediary of a lever, whereby the air escapes from the cylinder and at the same time the current circuit is interrupted by means of a microswitch connected with this piston while the feeler lever is still in operative position.

The return of the plunger armature and the rocker lever with the punching dies is effected in known manner by means of springs, whereby the piston in retracting positively sucks according to the invention air through a nozzle on the termination of the punching operation and brings the second microswitch back into its initial position, thereby terminating the period of delay.

The removal of the perforated material without friction is effected, according to the invention, by a delayed action through the intermediary of the air cylinder or also on a relay.

The armature constructed as a hollow body accom modates in its interior elastic material such as rubber fixed at the bottom end of the hollow body with its free end projecting beyond the lower edge thereof.

Owing to the fact that all the elements constituting the into the feed slot 13 that driving means are accommodated in a hood-like cover which is fixed on a base plate, the construction is compact and handy.

Punching apparatus constructed according tothe invention ensure that the sheets of paper to be punched can be easily removed after being perforated. The delay action device provided enables the removal to be carried out quickly and also in a reliable manner. The automatic contact-making renders it possible to use one hand for inserting the material to be punched, leaving the other hand free for picking up and preparing further material, and so forth. in addition the apparatus, due to the selection of particularly suitable individual elements, is not expensive and unites all the necessary parts in a single housing. Consequently the continuous, unhampered operation which it is sought to attain is rendered possible with the apparatus.

A preferred embodiment of the invention is illustrated by way of. example in the accompanying drawing, in which FIG. 1 shows the apparatus according to the invention in longitudinal section, and

FIG. 2 is a top plan view of the apparatus without cover.

on a base plate It a magnet housing comprising an alternating current coil 3 with a solid iron yoke 2 is fixed, the

coil 3 being fed directly from the mains supply by a cable 4. A plunger armature 5 is vertically movable in the solid iron yoke 2 and the coil 3. This armature 5 is drawn into the housing by magnetic force and acts on a one-armed rocker lever 8 pivoted on an axle 7 through the intermediary of a strap 6.

Two punching dies 10 interconnected by a cross axle 11 are mounted in bearings 9 in a plate 12 and a plate 12a on the plate 12. They are under the action of a return spring and slide axially. This punching arrangement comprising the parts 8 to 12a is arranged on the yoke 2. Between a hood or dome-like cover 14 and the plate 12a a feed slot 13 is provided for slipping in the material to be punched.

After loosening screws, this punching arrangement can be removed and exchanged for example for another with different hole spacing and is inaccessibly enclosed by the cover 14. Below this arrangement a drawer-like catching box 15 with a handle 16 is provided for the punching waste, which box rests on the base plate 1 and is slidable like a drawer in an aperture provided in the cover 14. A supporting plate with standard marking is also provided on the cover 14.

An important feature of such a punching apparatus is that, during the punching operation, i.e. when the plunger armature 5 comes into contact with the base plate 1, the impact is scarcely audible. With this object, the armature 5 is constructed as a hollow body. The hollow space is filled at its lower end with a solid elastic body, for example of rubber, not shown in the drawing, in such a manner that this body projects downwardly beyond the edge of the hollow body. Consequently, during operation, only the projecting end of the elastic solid body and no metal parts of the hollow body come into contact with the base plate. Thus all disturbing noise is avoided on the impact. I

To further reduce the noises when punching, at least the one-armed rocker lever 8 and the plate 12a are made from some suitable plastic substance.

When the apparatus has been connected up with the mains supply by means of the cable 4 it is ready for use without any special switching operation being necessary. The material to be punched is introduced in the feed slot 13 and after being punched is removed there from. When introducing the material it is pushed so far its edge actuates a feeler lever 23 of a microswitch 22,'with the result that current is supplied to the coil 3. Under the action of the magnetic force the plunger armature 5 is drawn into the coil 3 and the rocker lever 3 connected with it by means 'oft the strap 6jare moved downwardly with the punching dies 10. As the plunger armature 5 approaches its end position a piston 19 ispressed downwardly in an air cylinder 18 by'means of a'lever 2t mounted on the plunger armature 5. As a result the air is expelled fromthe cylinder 18 through a sleeve and at the same time a microswitch 21 connected with the piston 19 is actuated and the circuit interrupted in spite of the facttthat the feeler lever 23 is still actuated by the'material acting on it.

. The return of the plunger armature 5 and the upward movement of the rocker lever 8 with the punching dies 1% are effected by a return spring arranged substantially in the middle of the punching arrangement, see FIG. 1. Immediately after the punching operation is terminated the piston 19 again sucks air slowly into the cylinder 18 through a nozzle 17, a spring acting on the piston being provided for this purpose. Thus a delayed action occurs which can be attained by a relayinstead of the air cylinder. This delayed action enables the perforated material to be withdrawn from the apparatus Without difiiculty. Thereafterthe apparatus is in a condition to carry out the next punching operation without any preliminary manipulations being necessary. 1 A push button 24 may be provided on the rear side of the apparatus, which button serves to interrupt the circuit in the case the apparatus, being overloaded due to too much material having been introduced in the feed slot 13. Moreover, a cushion 25 of any suitable material may be attached to the inside of the cover .14 in such a manner that it lies directly on the rocker lever 8 and the bearings 9. a

The invention may be embodied inother specific forms without departing from the spirit or essential characteristics thereof. The present embodiment is therefore to strictive, the scope of the invention being indicated by the appended claim rather than by the foregoing description and all changes which come within the meaning and range of equivalency of the claim are therefore intended to be embraced therein.

We claim: v

An alternating current punch for punching paper, cardboard, pasteboardand the like, in combination with conbe considered in all respects as illustrative and not reventional axially shiftable punching dies, an electromagnetic drive with direct connection to the main current supply and comprising an electromagnet and an associated plunger armature with the armature operating said punching dies, a feeler lever extending into the path of insertion of material to bepunched and actuated thereby, a microswitch cooperating with said feeler lever to feed current to said electromagnet on the insertion of the material to be punched, a second microswitch cooperating with said plunger only after the punch has been movedto such an Xtent to cause punching of the Work material and causing deenergization of the electric circuit during :such time as it is operated, a time retarding device controlling said second microswitch to interrupt the current for a predetermined time to allow the removal of the punched material, the retarding device including a'lever which is coordinated with the plunger armature and adapted to act, when the plunger armature descends, on a springsupported piston in an air cylinder to expel the air from said cylinder and interrupt the current through the intermediary of the second microswitch connected with said piston only after such time as the punch has completed its punching stroke and While the feeler lever is still in operative position, a rocker lever pivoted on an axle and the plunger armature and the rocker lever together with the punching dies being arranged to quickly return into their initial positions by return means, whereas the piston in retracting on the completion of the punching operation positively sucks air into the cylinder and moves more slowly due to the delaying action of the retarding device through a nozzle and on reaching its initial position releases the second rnicroswitch after the punching dies have returned to their normal positions whereby time is provided for the removal of the material being punched.

7 References Cited in the file of this patent UNITED STATES PATENTS 

